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llnrran STATES ATENT Orrrca,

ALEXANDER PARKES, OF DULWICH, COUNTY OF SURREY, ENGLAND.

PROCESS OF EXTRACTING GOLD AND OTHER METALS FROM SULPHIDE ORES 0RCOMPOUNDS CONTAINING THE SAME.

SPECIFICATION forming part of Letters Patent No. 392,929, dated November13, 1888.

Application filed April 12, 1887. Serial No. 234,546. (No specimens)Patented in England October 13, 1886, No. 13,073 in Queensland May 4,1887, No. 349; in Italy September 9, 1887, XLIV, 56; in France September10,1887, No. 185,753; in Belgium September 13, 1887, No. 78,869; inGermany September 15, 1887, No. 3,449 in Spain September 16, 1887,-inIndia October 8, 1887, No. 308; in Canada October 13, 1887, No. 45,418;in New Zealand October 17,1887, No. 2,584; in Victoria October 28, 1887,No. 5,405; in New South Wales October 31, 1887, No. 305; in SouthAustralia November 3, 1887; in Cape Colony November 8, 1887, 414; inNatal November 16,1887; in Portugal November 18, 1887, No. 1,322; inTasmania November 21, 1887, No. 509,

and in Brazil November 30, 1887, No. 537.

To aZZ whom it may concern.-

Be it known that I, ALEXANDER PARKES, a subject of the Queen of GreatBritain and Ireland, residing at 8 Chancellor Road, Dulwich, in thecounty of Surrey, England, have invented certain new and usefulImprovements in Extracting Gold and other Metals from Sulphide Ores orCompounds Containing the Same, (for which I have obtained Letters Patentin Great Britain, No. 13,073, dated October 13, 1886; Italy, September9, 1887 N o. 56, Vol. XLIV; France, September 10,1887, No. 185,753;Belgium, September 13, 1887, No. 78,869; Germany, September 15, 1887,No. 3,449--Letters Patent allowed but not yet issued; British India,October 8, 1887, No. 308; New Zealand, October 17, 1887, No. 2,584;Victoria, October 28, 1887, No. 5,405; New South Wales, October 31, 1887No. 305; Cape Colony, November 8, 1887, folio 414; Natal, November 16,1887 Tasmania, November 21, 1887, No. 509; Brazil, November 30, 1887,No. 537; Queensland, May 4, 1877, No. 349-Letters Patent not yetgranted; Spain, September 16, 1887; Canada,0ctober 13, 1887, No.4.5,418Letters Patent not yet granted; South Australia, November 3,1887, and Portugal, November 18, 1887, No.1,322-Letters Patent not yetgranted;) and I do hereby declare that the following is a full, clear,and exact description of the invention, which will enable others skilledin the art to which it appertains to make and use the same.

This invention relates to the treatment of auriferous ores of thesulphide class for the extraction of the gold, silver, and other metalscontained therein by means of an economical and expeditious processwhich enables, practically, the whole of the precious metals to beseparated, and whereby the usual preliminary operation of calcining theore is dispensed with.

In treating refractory ores of the class above referred to, and whichfrequently contain gold, silver, copper, and other metals, I crush orgranulate the ore and melt it in a reverbera tory or other suitablefurnace with fluxes composed, by preference, of alkaline or earthysulphates or chlorides, and containing carbon or to which carbon isadded. To the mixture of ore and flux is added lead or oxidized orsulphur compounds of lead,with the object of collecting all the preciousand other metals sought to be recovered. These completely separate fromthe slag, and, the latter having been removed,a metallic compound isobtained in a condition suitable for treatment by what is known asParkes desilverizing process, or by other known methods for separatingthe gold and other metals contained in such compound. In some instancesthe ore in its natural stat contains sufficient lead to render theaddition,

as above mentioned, of lead or oxidized or sulphur compounds of leadunnecessary, in which case a sufficient quantity of the lead naturallycontained in the ore is reduced and combines with and serves to collectthe gold (and silver, if any) contained in the ore.

Instead of adding lead in the furnace, as above described, a regulus maybe obtained as the result of the process of smelting the mixture of oreand flux, and this regulus may be treated with lead or the compounds oflead before mentioned.

The regulus obtained as the result of smelting sulphide ores with thecompound flux of the kind hereinbefore specified possesses the peculiarproperty or tendency to disintegrate and resolve itself into a finepowder by more exposure for a few hours to the atmosphere. This effect,which resembles that to which quicklime is subject, may be expedited bysprinkling the regulus, while hot, with water. In such finelydividedstate the regulus is specially adapted for treatment with lead or byother known methods for separating the gold and other metalscontainedtherein. Furthermore, the metallic sulphides being collected ina concentrated mass, the quantity of material or regulus requiringfurther treatment is of comparatively small bulk.

The particular fluxing substances most appropriate for different kindsof ore will vary to some extent according to whether the ores arecombined with silicious or other earthy matters. The proportions inwhich the fluxing substances are used will also be subject to variation.

In applying my improved process, by way of example, to ores such as areobtained from the Ravenswood mines of Queensland, I employ, for each tonof such ore, three to four hundred-weight of caustic lime, (bypreference,) in combination with either one hundred-Wei ght of causticsoda or the same quantity of sulphate or bisulphate of soda,or half thatquantity of silicate of soda, from one-half to one hundred weight ofcarbon being added.

Instead of a reverberatory furnace, a cupola or blast furnace may beemployed for melting the ore; but in any case I regard it not merely asunnecessary, but as undesirable, that the ore should be subjected in thefirst instance to calcination for the purpose of driving off the sulphurcontained therein. I have found that Without calcining the ore themetals reduced separate very perfectly from the slag, and that thelatter is left remarkably free of the precious metals. Furthermore, bymy improved process, the use both of amalgamation and of chlorinationmay be dispensed with, an improved result being at the same timeattained.

The ore may with advantage be crushed to a moderate size before beingplaced in the furnace; but the usual. process of grinding it to a finepowder is rendered unnecessary.

I also regard as an important feature of my invention the use, incombination with caustic lime or limestone, of caustic soda, or nitrate,silicate, or carbonate of soda,or sulphur compounds of soda, the samebeing employed in conjunction with carbon, loss of gold and silver beingprevented by the use of such fluXing substances in combination. Theyalso react upon one another in such a manner as to produce greatfluidity and to permit of a given quantity of refractory ore beingtreated with a far smaller quantity of fiux than by any laboratory orother process with which I am acquainted, my improved process beingthereby rendered commercially practicable.

Having now fully described my invention, what I desire to claim andsecure by Letters In testimonywhereofl have signed my name to thisspecification in the presence of two subscribing witnesses.

ALEXANDER PARKES.

\Vituesscs:

JAMES W. SDLYL'LHAN, O. XV. Lnns.

